目標：探討新制醫院評鑑納入處方警示系統項目與門診重複用藥率的變化情形。方法：資料來源是2005年百萬承保抽樣歸人檔，擷取2003-08年各年有18歲以上病人西醫門診處方案件之地區級以上醫院320家。重複用藥係指病人在重疊日期接受院內不同醫師開立之處方含ATC(Anatomical Therapeutic Chemical)前四碼相同藥品，院內重複用藥處方率=(院內重複用藥處方數/院內重疊日期處方數)*100%。新制醫院評鑑處方警示系統項目施行時間分為實施前(2003-04年，T0)、試辦期(2005-06年，T1)、實施後(2007-08年，T2)；其他控制因素包括醫院層級別、權屬別、醫院所屬分局別。統計方法為描述性統計與廣義估計方程式(GEE)。結果：新制醫院評鑑實施前平均院內重複用藥處方率是46.28%，試辦期40.23%，實施後32.95%。院內重複用藥相關因素分析在控制其他變項後發現，2005-06年(T1)的院內重複用藥處方率減少6.08個百分點(p=0.0008)；而2007-08年(T2)則減少13.13個百分點(p<0.0001)。結論：新制醫院評鑑處方警示系統和院內門診重複用藥的改善有相關。(台灣衛誌 2014；33(5)：523-529)

Objectives: To understand changes in the medication duplication rate after implementation ofa prescribing alert system as a new criterion for hospital accreditation. Methods: We studied 320general hospitals that provided prescriptions for outpatients aged 18 and older in 2003-2008 fromthe longitudinal NHI dataset. Medication duplication was defined as "a patient received drugs withthe same therapeutic effect (as defined by level 3 of the Anatomical Therapeutic Chemical system)with different prescriptions provided by different physicians from the same hospital within onetreatment period". Medication duplication rate = (cases of medication duplication) / (total numberof prescription provided in a hospital within same treatment period) x 100%. There were threeobservation periods: before the new criterion for hospital accreditation was implemented (years2003-04, T0), the period of pilot implementation (years 2005-06, T1), and after the new criterionfor hospital accreditation was implemented (years 2007-08, T2). The data were adjusted foraccreditation status, ownership, and branch of BNHI, and descriptive statistics and GEE wereused in the analysis. Results: The average rate of medication duplication in hospitals was 46.28%in years 2003-04 (T0), 40.23% in years 2005-06 (T1), and 32.95% in years 2007-08 (T2). Aftercontrolling for other factors, the medication duplication rate decreased by 6.08 percentage points(p=0.0008) in years 2005-06 (T1), and 13.13 percentage points (p<0.0001) in years 2007-08 (T2).Conclusion: The addition of an alert system for duplicate prescriptions as a criterion for hospitalaccreditation was associated with improvement in the medication prescribing practices in hospitaloutpatient departments. (Taiwan J Public Health. 2014;33(5):523-529)